In the construction of pneumatic tires, annular belt or belts (called "breakers") have been generally included about the circumference of the tire between the tire carcass body and the tread. Such belts provide better road stability and longer tread life in both radial and bias ply tires.
Even with such belts or breakers, there has been a continuing need for a stronger, more durable, more wear-resistant, lighter weight pneumatic tire. One of the approaches used in the past to increase durability and wear resistance, while reducing weight, has been to vary the weave and composition of the reinforcing threads and cords of the plys. Various illustrations of this approach are set forth in U.S. Pat. Nos. 688,319, 1,423,771, 2,083,003, 2,906,314, 3,481,386, 3,568,749 and 3,682,222.
Generally such reinforcements utilize cords and wires coated with or impregnated in suitable elastomeric material such as natural or synthetic rubber. For radial ply tires, inextensible belts with such cords disposed in the direction of the longitudinal axis of the belt can be readily made by calendaring woven fabric with an unvulcanized rubber. However, the cords are usually disposed in a bias pattern in which portions thereof extend in different directions to each other and generally in directions biased with respect to the longitudinal axis of the reinforcement. This pattern is usually provided by cutting on a bias woven fabric which has been calendared with a layer of unvulcanized rubber, and thereafter splicing the cut strips edge to edge.
Another approach to the problem of increasing durability and wear resistance, while reducing weight, has been to interleave strips or plys of rubber coated or impregnated reinforcing material to form bands or belts for use in the carcass or breaker of the pneumatic tire. Illustrative of the different disclosures directed to this approach are set forth in U.S. Pat. Nos. 574,438, 1,017,271, 1,132,634, 1,233,420, 3,024,829 and 3,770,042. Of this approach, it has been general knowledge that the strips must be biased to the circumference of the tire to allow inflation to the desired tension, and to provide sufficient flexibility that the tire will readily yield to the various surfaces encountered during use without substantial heat generation.
The present invention goes contrary to those teachings of the prior art. Surprisingly, the present invention provides a highly durable and wear resistant tire of light weight by incorporating a breaker belt formed of circumferential bands interleaved with angularly disposed strips.